643401 has 24 divisors (see below), whose sum is σ = 1039584. Its totient is φ = 380160.

The previous prime is 643373. The next prime is 643403. The reversal of 643401 is 104346.

It is not a de Polignac number, because 643401 - 2⁵ = 643369 is a prime.

It is an Ulam number.

It is a nialpdrome in base 15.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 643401.

It is not an unprimeable number, because it can be changed into a prime (643403) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6585 + ... + 6681.

It is an arithmetic number, because the mean of its divisors is an integer number (43316).

2⁶⁴³⁴⁰¹ is an apocalyptic number.

It is an amenable number.

643401 is a deficient number, since it is larger than the sum of its proper divisors (396183).

643401 is a wasteful number, since it uses less digits than its factorization.

643401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181 (or 178 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 643401 is about 802.1228085524. The cubic root of 643401 is about 86.3297686729.

Adding to 643401 its reverse (104346), we get a palindrome (747747).

The spelling of 643401 in words is "six hundred forty-three thousand, four hundred one".